Datasheet

360
7766F–AVR–11/10
ATmega16/32U4
Note: 1. The timing requirements shown in Figure 28-7 (i.e., t
DVXH
, t
XHXL
, and t
XLDX
) also apply to read-
ing operation.
Notes: 1. t
WLRH
is valid for the Write Flash, Write EEPROM, Write Fuse bits and Write Lock bits
commands.
2. t
WLRH_CE
is valid for the Chip Erase command.
28.7 Serial Downloading
Both the Flash and EEPROM memory arrays can be programmed using a serial programming
bus while RESET
is pulled to GND. The serial programming interface consists of pins SCK, PDI
(input) and PDO (output). After RESET
is set low, the Programming Enable instruction needs to
be executed first before program/erase operations can be executed. NOTE, in Table 28-14 on
page 361, the pin mapping for serial programming is listed. Not all packages use the SPI pins
dedicated for the internal Serial Peripheral Interface - SPI.
Table 28-13. Parallel Programming Characteristics, V
CC
= 5V ± 10%
Symbol Parameter Min Typ Max Units
V
PP
Programming Enable Voltage 11.5 12.5 V
I
PP
Programming Enable Current 250 μA
t
DVXH
Data and Control Valid before XTAL1 High 67 ns
t
XLXH
XTAL1 Low to XTAL1 High 200 ns
t
XHXL
XTAL1 Pulse Width High 150 ns
t
XLDX
Data and Control Hold after XTAL1 Low 67 ns
t
XLWL
XTAL1 Low to WR Low 0 ns
t
XLPH
XTAL1 Low to PAGEL high 0 ns
t
PLXH
PAGEL low to XTAL1 high 150 ns
t
BVPH
BS1 Valid before PAGEL High 67 ns
t
PHPL
PAGEL Pulse Width High 150 ns
t
PLBX
BS1 Hold after PAGEL Low 67 ns
t
WLBX
BS2/1 Hold after WR Low 67 ns
t
PLWL
PAGEL Low to WR Low 67 ns
t
BVWL
BS2/1 Valid to WR Low 67 ns
t
WLWH
WR Pulse Width Low 150 ns
t
WLRL
WR Low to RDY/BSY Low 0 1 μs
t
WLRH
WR Low to RDY/BSY High
(1)
3.7 4.5 ms
t
WLRH_CE
WR Low to RDY/BSY High for Chip Erase
(2)
7.5 9 ms
t
XLOL
XTAL1 Low to OE Low 0 ns
t
BVDV
BS1 Valid to DATA valid 0 250 ns
t
OLDV
OE Low to DATA Valid 250 ns
t
OHDZ
OE High to DATA Tri-stated 250 ns